Processes and devices of this kind are known from e.g., DE 2616523. In the past, these processes and devices have proved to be very suitable, among other things, for fastening heat exchanger tubes in heat exchangers or in the manufacture of camshafts for automobile engines.
Since very high pressure can be developed using hydraulic processes and plants, the individual components that are subject to pressure manifest signs of material fatigue in due course of time. This can endanger the application security of the expansion device. Hence the application of expansion devices is monitored with regular maintenance. The maintenance involves exchanging a multitude of pressurized components depending on predefined maintenance intervals. Thus the maintenance intervals restrict the application of the expansion devices. Due to the great success of these hydraulic plants it is increasingly desired to use the devices for hydraulic expansion more often and/or for longer periods of time than was possible so far.